If the file you’re trying to access is on a disk that’s not currently connected to the computer you’re using, all you need to do is reconnect the disk, and Lightroom will be able to access the file again. No real problem there.

However, if you moved, deleted, or renamed the file outside of Lightroom, you need to update the catalog with this new information so that it can be happily reunited with your file again. Let’s go through the process of correcting each situation.

The easiest situation to fix is the case where you deleted a file outside of Lightroom. All you need to do here is select the thumbnail in Grid view and press Delete. When prompted, click Remove. This action removes the file from the catalog and thereby brings Lightroom up to date with the reality of that file.

If the file was moved or renamed, the process is a little more involved, but not too painful. Here are the steps from Grid view:

Click the question mark icon on the thumbnail. This will open a dialog box that asks whether you’d like to try to locate this missing file. You will also see the path that Lightroom has stored in its catalog for that file. This information may help you to remember what happened to that file. Did you do a bit of housekeeping and shuffle files around? Did you do a batch renaming in Bridge because you like it better? Did the drive letter change on the external drive since the photo was imported? Your job is going to be reuniting Lightroom with that file, so hopefully that piece of information is enough to lead you to where the file is actually located.

Click the Locate button.

Navigate to the location of the file, select it, and click Open (Windows) or Select (Mac).

That’s it. Lightroom will update its catalog to reflect this new information, and you’ll be on your way.

If you encounter a situation where an entire folder is considered offline or missing, you can follow a similar process to bring Lightroom up to speed. Lightroom displays offline folders in red within the Folders panel. To reconnect the folder, right-click it, choose Locate Missing Folder and go through the same process just described for a single photo. Once the reconnection has been made to the folder, Lightroom will update the location information for all the photos contained inside the folder.

The best way to avoid ever having to go through that process is to always perform your housekeeping inside of Lightroom. That means do all your renaming, moving, and deleting from within Lightroom. This not only gets the job done, but it keeps the catalog up to date at the same time.